1. Field of the Invention
The present invention relates to an electronic endoscope system, which comprises a plurality of electronic endoscopes and peripheral devices, such as TV monitors or VCR""s (video cassette recorder).
2. Description of the Related Art
In recent medical practice, various types of electronic endoscope systems, such as the RGB sequential or color chip systems, an ultrasonic systems, a system that captures a fluorescent image of exited cells in the interior of a hollow organ and so on, are used. Each electronic endoscope system is selectively utilized as the occasion may require. In electronic endoscopy, dissimilar to optical endoscopy that observes an optical image at the distal end of a fiber-optic bundle, an imaging device, such as a TV monitor, is required to observe the image captured by the above electronic endoscope.
In a large number of medical facilities, several types of electronic endoscope systems are utilized during a single checkup or medical examination since each type of electronic endoscope system has an exclusive purpose. In these facilities, it is the dissipation of space and cost of peripheral devices, such as TV monitors, video cassette recorders and so on, provided for each electronic endoscope system. It is also cumbersome and time consuming to operate the peripheral devices individually prepared for each system.
Therefore, it is preferable to share devices that have a common function among the electronic endoscope systems, such as a TV monitor, video cassette recorder (VCR), etc., and build a single organized electronic endoscope system. In order to share the peripheral devices among the plurality of electronic endoscope systems and build an organized electronic endoscope system, an electronic endoscope selector that mediates between each of the electronic endoscopes and the- peripheral devices is required.
The above organized electronic endoscope system comprises a plurality of electronic endoscope units, each of which comprises an endoscope with an elongated part for insertion into a body cavity or hollow organ, and an image-signal processing unit that processes image signals fed from an imaging device mounted on the distal end of the elongated part of the endoscope. Images captured by the imaging device are output from the image-signal processing unit to the electronic endoscope selector as video signals with a synchronizing signal. It takes time for the TV monitor to synchronize with the synchronizing signal fed from the newly selected electronic endoscope and if the electronic endoscope selector simultaneously switches both video signals and synchronizing signal from one electronic endoscope unit to another, unsynchronized video will be displayed on the TV monitor while the TV monitor is synchronizing with the synchronizing signal. Therefore, the electronic endoscope operator inevitably observes unsynchronized image on the TV monitor while the TV monitor is engaged in the synchronizing operation. This causes eyestrain to the operator, especially when the TV monitor is used in a darkened room to improve the observation of the image.
Therefore, an object of the present invention is to provide an electronic endoscope selector that enables a plurality of electronic endoscopes to share a peripheral device and integrate a plurality of electronic endoscope systems into a single organized electronic endoscope system. Further, the object of the present invention is to provide the electronic endoscope selector, which sends video of a selected electronic endoscope to a peripheral device without unsynchronized video when the electronic endoscope is switched to another electronic endoscope.
According to the present invention, there is provided an electronic endoscope selector comprising a video signal switching processor, a synchronizing signal switching processor and a switching control processor.
The video signal switching processor switches video signals, output to at least one peripheral device, between first video signals fed from a first electronic endoscope to second video signals fed from a second electronic endoscope. The synchronizing signal switching processor switches synchronizing signals, output to the peripheral device, between synchronizing signals fed from the first electronic endoscope to synchronizing signals fed from the second electronic endoscope. The switching control processor drives the video signal switching processor and synchronizing signal switching processor and suspends output of the video signal for a predetermined period after driving the synchronizing signal switching processor.
Preferably, the electronic endoscope selector comprises an operating processor for driving the switching control processor.
The switching control processor may drive the video signal switching processor and the synchronizing signal switching processor simultaneously. In this case, preferably, the switching control processor comprises an output switching processor and a timer. The output switching processor switches the video signals between the xe2x80x98ONxe2x80x99 and xe2x80x98OFFxe2x80x99 states. The ON state permits and the OFF state forbids output of the video signals. The timer is used for timing the predetermined period. Further, the output switching processor is set to xe2x80x98OFFxe2x80x99 and the timer is started when the synchronizing signal switching processor is driven. Furthermore, the output switching processor is switched to xe2x80x98ONxe2x80x99 after the predetermined period. The xe2x80x98ONxe2x80x99 and xe2x80x98OFFxe2x80x99 states for output control of the video signals from the video signal switching processor are switched by the output switching processor.
In another preferable example, the switching control processor drives the video signal switching processor for a predetermined period after driving the synchronizing signal switching processor, and suspends output of the video signals for a predetermined period.
Further, preferably, the signal switching processor comprises a first and second buffer circuit and the switching control processor comprises a first and second timer.
The first buffer circuit, to which input the first video signals are fed from the first electronic endoscope, controls the ON and OFF states of video signal output. The ON state permits video signal output, and the OFF state forbids video signal output. The second buffer circuit, to which input the second video signals are fed from the second electronic endoscope, controls the ON and OFF state of the video signal output. The first timer sets the first buffer circuit to the OFF state, which forbids output of the video signals, immediately after receipt of a control signal. The second timer sets the second buffer circuit to xe2x80x98OFFxe2x80x99 state immediately after input of a control signal. It also sets the second buffer circuit to xe2x80x98ONxe2x80x99 after a predetermined period from control signal input completion. Therefore, switching of the first and second video signals is controlled by the control signal, which is input alternately to the first and second timer.
Furthermore, the synchronizing signal switching processor comprises a third and fourth buffer circuit. The third buffer circuit receives synchronizing signals from the first electronic endoscope and controls the ON and OFF states of synchronizing signal output. The ON state permits output of the synchronizing signals and the OFF state forbids output. The fourth buffer circuit receives synchronizing signals from the second electronic endoscope and controls the ON and OFF states of synchronizing signal output. Switching the synchronizing signals is controlled by alternating the ON and OFF states of the third and fourth buffer circuits.